1. Technical Field
The present invention relates to a liquid ejecting head and a liquid ejecting apparatus.
2. Related Art
As a representative example of a liquid ejecting head, an ink jet printhead of capable ejecting ink drops from nozzles is exemplified. The ink jet printhead generally includes a plurality of pressure generating chambers which communicate with nozzles and a reservoir (common ink chamber) which communicates the plurality of pressure generating chambers (cavity) respectively. Ink stored in a storage unit such as an ink cartridge is taken into the reservoir, is supplied from the reservoir to the respective pressure generating chambers, and is pressurized by a piezoelectric actuator or the like, so that the ink drops are ejected from the nozzles.
As the ink jet printhead described above, the one having a filter for removing foreign substances in ink disposed in a channel which communicates a storage unit and a reservoir is disclosed in JP-A-2007-76093 and JP-A-2003-311951.
As the filter described above, there are types such as those formed by electroforming or those formed by punching a number of filter holes (fine holes) through a metal or a resin film. However, either of these filters might suffer from occurrence of warp (curl) at the time of manufacture. Then, in the case of a structure in which a filter is joined on a substrate having ink flow channels such as the pressure generating chamber formed thereon, there arise problems such as defective joining caused by the curl of the filter (for example, separation of the filter) or deterioration of positioning accuracy of the filter with respect to the substrate, whereby desirable supply of ink to the reservoir via the filter might fail. For example, in JP-A-2006-272806, provision of concavo-convexo on a metal film as a filter for restraining curl is proposed. However, even with this structure, it is also difficult to restrain occurrence of curling completely.
Even with the structure in which the filter is integrated in a thin plate laminated with a substrate formed with the ink flow channels as described in JP-A-2003-311951, there might occur problems such as the defective joining and defective ink supply due to the occurrence of the curl on the periphery of the filter.
These problems are present not only in the ink jet printhead which ejects ink drops, but also in the liquid ejecting head ejecting other liquid drops.